the skull - judoctors · the middle cranial fossa is separated from the posterior cranial fossa by...

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The Skull The skull is composed of several separate bones (22 bones) united at immobile joints called sutures. The connective tissue between the bones is called a sutural ligament The upper part of the cranium is The vault The base of the skull is the lowest part of the cranium The skull bones are made up of External and internal tables of compact bone separated by a layer of spongy bone called the diploic bones The bones are covered on the outer and inner surfaces with periosteum. Only one moveable bone, the mandible which is united to the skull by the mobile Temporomandibular Joint The bones of the skull can be divided into: 1- Bones of the cranium (contain the brain) 2- Bones of the face

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Page 1: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

The SkullThe skull is composed of several separate

bones (22 bones) united at immobile joints

called sutures.

The connective tissue between the bones

is called a sutural ligament

The upper part of the cranium is The vault

The base of the skull is the lowest part of the cranium

The skull bones are made up of

External and internal tables of compact bone separated

by a layer of spongy bone called the diploic bones

The bones are covered on the outer and inner surfaces

with periosteum.

Only one moveable bone, the mandible which is

united to the skull by the mobile

Temporomandibular Joint

The bones of the skull can be divided into:

1- Bones of the cranium (contain the brain)

2- Bones of the face

Page 2: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

A) The cranium consists of the

following bones

two of which are paired :

Frontal bone: 1

Parietal bones: 2

Occipital bone: 1

Temporal bones: 2

Sphenoid bone: 1

Ethmoid bone: 1

B)The facial bones consist of

the following

two of which are single:

Zygomatic bones: 2

Maxillae: 2

Nasal bones: 2

Lacrimal bones: 2

Vomer: 1

Palatine bones: 2

Inferior conchae: 2

Mandible: 1

Page 3: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

Norma Frontalis

It is the anterior aspect of the skull

Made of three parts

1-Upper part: Forehead; made of

the frontal bone

2-Middle part: contains 3 caviteis;2

orbital & 1 nasal

3-Lower part: formed by the upper

& lower jaws

Page 4: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

1- Frontal eminence: the most prominent

areas on either side of the forehead

2-The superciliary arches

:Elevated ridges above the medial

parts of the sup. Orbital margins

3-supraorbital notch, or

foramen: located on junction

between the medial 1/3 and the

lateral 2/3. transmits the

supraorbital n. & vessels

4-Glabela:an area above the root

of the nose Between the 2

superciliary arches

5-Nasion:a point where the

frontonasal & interanasal

sutures meet

6-The nasal bones: form

the roof of the nose

Page 5: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

The orbital margins are bounded by:

A-The frontal bone :superiorly

B-The zygomatic bone :laterally

C- The maxilla: inferiorly

D-The processes of the maxilla and

frontal bone :medially

7-The zygomatic bones has:

a-Frontal processes: articulates with

frontal bone

b-Temporal processes: articulates with

zygomatic process of the temporal bone

to form the zygomatic arch

c- maxillary processes: articulates with

the maxillary bone

d- orbital plate: shears in the formation

of the floor and lateral wall of the orbit

a-Frontal processes:

b-Temporal

processes:

c- maxillary processes

d- orbital plate

The zygomatic bone

Page 6: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

The parietal bones form the

sides and roof of the cranium.

The skull is completed at the side

by the

1-Squamous part of the occipital

bone

2-Parts of the temporal bone

The squamous

Tympanic

Mastoid process

Styloid process

3-Zygomatic process

4- The greater wing of the

sphenoid

Note the position of the external

auditory meatus.

The ramus and body of the

mandible lie inferiorly.

.

Norma lateralis

Page 7: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

Identify

the superior and inferior temporal

lines, which begin as a single line from

the posterior margin of the zygomatic

process of the frontal bone and diverge

as they arch backward.

The upper temporal line gives

attachment for the temporal fascia

The lower temporal line is for the

attachment of temporalis muscle

The supramastoid crest

The zygomatic arch: formed

of the temporal process of

The zygomatic process of temporal

bone and the zygomatic process of

temporal bone (its lower border And

inner surface give attachment to the

masseter muscle

Page 8: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

The pterion is the thinnest part of the

lateral wall of the skull. it overlies the

anterior division of

The middle meningeal artery and vein

Pterion: is an area located on the floor of

the temporal fossa

Where 4 bones meet at an H-shaped

structure

The 4 bones are

1-freontal

2- parietal

3-squamous part of temporal bone

4-greater wing of sphenoid

Epidural bleeding

Page 9: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

The temporal fossa lies below the

inferior temporal line

The infratemporal fossa

lies below the infratemporal crest on

the greater wing of the sphenoid

The zygomatic arch divides the lateral

side of the Skull into

The temporal fossa & The

infratemporal fossa

Page 10: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

The temporal fossa

Boundries

Above and behind: the superior temporal line

Below: The zygomatic arch

Anteriorly: the frontal process of zygomatic

bone

Infratemporal fossa

Anterior wall: back of the maxilla

Medial wall: lateral pterygoid plate

Roof: infratemporal surface of the

greater wing Of sphenoid bone

Lateral wall: ramus of mandible

Communications

Temporal fossa: through the gap deep to

the zygomatic arch

Orbit: through the inferior orbital fissure

Pterygo-polatine fossa : through the

pterygo-maxillary fissure

Page 11: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

The pterygomaxillary fissure is

a vertical fissure that lies within the

fossa between the pterygoid

process of the sphenoid bone and

back of the maxilla. It leads

medially into the pterygopalatine

fossa.

The inferior orbital fissure

is a horizontal fissure between the

greater wing of the sphenoid bone

and the maxilla.

It leads forward into the orbit.

Page 12: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

The pterygopalatine fossa

Is a small space behind and below

the orbital cavity.

It communicates

laterally :with the infratemporal

fossa through the pterygomaxillary

fissure

Medially: with the nasal cavity

through the sphenopalatine

foramen

superiorly :with the skull

through the foramen rotundum

anteriorly :with the orbit through

the inferior orbital fissure

Page 13: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

Superior View of the Skull

(Norma Verticalis)Anteriorly

the frontal bone articulates with the

two parietal bones

AT THE CORONAL

SUTURE

The two parietal bones articulate in

the midline

AT THE SAGITTAL

SUTURE

lambdoid

sutures

Page 14: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the
Page 15: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

Above The posterior parts of the two

Parietal bones with the intervening

sagittal suture

Below, the parietal bones articulate with the

squamous part of the occipital bone

at the lambdoid suture.

On each side the occipital bone

articulates with the temporal bone.

In the midline of the occipital bone is

a roughened elevation called

The external occipital protuberance

which gives attachment to muscles

and the ligamentum nuchae

Posterior View of the Skull

On either side of the protuberance the

superior nuchal lines extend laterally

toward the temporal bone.

Page 16: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

The middle cranial

fossa is separated from

the posterior cranial

fossa By

The petrous part of

the temporal bone

1-Anterior

2-Middle

3-Posterior

Base of the Skull

The interior of the base of the skull is

divided into three cranial fossae:

The anterior cranial fossa

is separated from

the middle cranial fossa

By

The lesser wing of the

sphenoid

2-M

idd

le

3-Posterior

1-Anterior

Page 17: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

Contains the frontal lobes of

the cerebral hemispheres

Anterior Cranial Fossa

It is bounded

Anteriorly: by the inner surface of the

frontal bone

In the midline: a crest galli for the

attachment of the falx cerebri.

Posteriorly :the lesser wing of the

sphenoid bone

Note: The medial end of the lesser wing of

the sphenoid forms

The anterior clinoid process

gives attachment to the

Tentorium cerebelli.

The floor of the fossa is formed by:

Laterally :orbital plates of the frontal bone

Medially: by the cribriform plate of the

ethmoid

The crista galli is a sharp upward

projection of the ethmoid bone in the

midline for the attachment of

The falx cerebri.

Page 18: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

formed by:

the body of the sphenoid It is bounded

Middle Cranial Fossa

Laterally :

the squamous parts of the temporal

bones, the greater wings of the

sphenoid,

and the parietal bones.

The floor of each lateral part of the

middle cranial fossa is formed by

the greater wing of the sphenoid and

the squamous and petrous parts of

the temporal bone.

Posteriorly by :the superior

borders of the petrous parts of

the temporal bones

Anteriorly by: the lesser wings

of the sphenoid

Page 19: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

1-The body of the sphenoid :contains the

sphenoid air sinuses

2-The optic canal transmits

A- The optic nerve

B-The ophthalmic artery

3-The superior orbital fissure

is a slitlike opening between

the lesser and greater wings

of the sphenoid transmits:

The sphenoid bone

resembles a bat having a centrally placed body

with greater and lesser wings that are

outstretched on each side

Page 20: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

Lacrimal

Frontal

Trochlear

Superior division of Oculomotor nerve

Nasociliary

Inferior division of oculomotor nerve

Abducent nerves

together with the superior ophthalmic vein.

Live

Free

To

See

No

Insult

At all

Page 21: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

4-The foramen rotundum

situated behind the medial end of the superior

orbital fissure

Transmits the maxillary nerve.

5-The foramen ovale

lies posterolateral to the foramen rotundum

Transmits the mandibular nerve

the lesser petrosal nerve

6-The small foramen spinosum

lies posterolateral to the foramen

ovale The foramen transmits

The middle meningeal artery

7-Foramen lacerum

lies between the apex of the petrous part of the

temporal bone and the sphenoid bone

in life is filled by cartilage and fibrous

tissue, and only small blood vessels pass

through this tissue from the cranial cavity to

the neck.

8-The carotid canal

Transmits: The internal carotid artery

9- Meckl’s cave:

impression on the apex of the petrous part of

the temporal bone for the trigeminal ganglion

Page 22: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

10-The median part of the middle cranial

fossa is formed by:

the body of the sphenoid bone

In front of it is

The sulcus chiasmatis

which is related to the optic chiasma

and leads laterally

To

THE OPTIC CANAL

On the superior aspect of the body is a

depression called

The sella turcicawhich CONTAIN

THE PITUITARY GLAND

The sella turcica is bounded posteriorly by

a square plate of bone called

THE DORSUM SELLAEThe superior angles of the dorsum sellae

have

two tuberclescalled

The posterior clinoid processes

which give attachment to the fixed

margin of

The tentorium cerebelli.

Page 23: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

Posterior Cranial Fossa

Contains the parts of the hindbrain:

The cerebellum, Pons, and Medulla

oblongata

The roof is formed by:

a fold of dura

THE TENTORIUM CEREBELLI

which intervenes between the

cerebellum below And

the occipital lobes of the cerebral

hemispheres above

Is bounded by:

Anteriorly: the petrous part of the temporal bone

Posteriorly : the internal surface of the

squamous part of the occipital bone

The floor is formed by:Parts of the occipital bone

The mastoid part of the temporal bone

Page 24: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

1-The internal acoustic meatus

pierces the posterior surface of the petrous part

of the temporal bone.

It transmits:

A- THE VESTIBULOCOCHLEAR NERVE

B- THE FACIAL NERVE.

3- Groove for the transverse sinus:

On each side of the internal occipital

protuberance

2-The internal occipital protuberance

attached to it the small falx cerebelli

Page 25: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

4-the sigmoid sinus

4-the sigmoid

sinus

Page 26: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

5-The foramen magnum

occupies the central area of the floor

Transmits

A- The medulla oblongata and its

surrounding meninges

B- The ascending spinal parts of the

accessory nerves

C-The two vertebral arteries

6-The hypoglossal canal

is situated above the anterolateral boundary

of the foramen magnum

Transmits the hypoglossal nerve

Page 27: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

7-The jugular foramen

It transmits the following structures:

from before backward:

A-The inferior petrosal sinus

B-The 9th, 10th, and 11th cranial

nerves

C- The large sigmoid sinus

D-The inferior petrosal sinus

E-The sigmoid sinus turns down

through the foramen

to become the internal jugular

vein

Page 28: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

Inferior View of the Skull

1-The hard palate whic is made of:

A-The palatal processes of the

maxillae (vertical)

B-The horizontal plates of the

palatine bones

2-Incisive fossa and foramen

3-The greater and lesser palatine

foramina

4-The choanae (posterior nasal

apertures).

5-The vomer

6-Medial and lateral pterygoid

plates

of the sphenoid bone

Page 29: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

9-The spine of the sphenoid

LOCATED Posterolateral to

the foramen spinosum is

The greater wing of the sphenoid is

pierced by the large

7-foramen ovale

8-foramen spinosum

10-The mandibular fossa of the temporal bone

and the articular tubercle form the upper

articular surfaces for the temporomandibular

joint.

Page 30: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

12-Tympanic plate of the

temporal bone

11-The styloid process of

the temporal bone

14-The opening of the

carotid canal

15- Foramen lacerum

13-the external

auditory meatus

Page 31: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

16- The stylomastoid foramen

In the interval between the styloid and mastoid

processe

17-jugular foramen

18-Hypoglossal canal

Superior to the occipital condyle

for transmission of the

hypoglossal nerve

Page 32: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the

19-The basilar part of the

occipital bone

20-The occipital condyles

21-The external

occipital

protuberance.

22- The superior nuchal lines :posterior to the

foramen magnum in the midline

Page 33: The Skull - JUdoctors · The middle cranial fossa is separated from the posterior cranial fossa By The petrous part of the temporal bone 1-Anterior 2-Middle 3-Posterior Base of the